Alkenyl phosphonitrilic ester-polyhalo-hydrocarbon adducts



United States Patent ALKENYL PHOSPHONITRILIC ESTER-PGLYHALG- HYDROARBON ADDUCTS Carl Hamalainen, Metairie, La., assignor to the United States of America as represented by the Secretary of Agriculture No Drawing. Application November E9, 1354 Serial No. 467,909

9 Claims. (Cl. 260-36)) (Granted under Title 35, U. S. Code (1952), see. 266.)

A non-exclusive, irrevocable, royalty-free license in the invention herein described, for all governmental purposes, throughout the world, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to novel partially unsaturated phosphorus, nitrogen, and halogen containing polymeric addition products in which the proportion of halogen and unsaturated groups can be varied over fairly wide limits.- More particularly, the invention provides textile treating liquids, comprising aqueous emulsions containing such addition products, which textile treating liquids are particularly efiective for reducing the flammability of textiles.

Numerous textiles which exhibit particularly good textile properties such as strength, hand, feel, and the like are fairly flammable. Numerous compositions which decrease the flammability of textiles have been developed, but none of them meet all of the desirable conditions which include being effective in small amount, being non-degradative of the chemical or textile properties of the textile, being non-volatile and resistant to both laundering and dry cleaning, and being effective at the ignition temperature at which the-textile is likely to be subjected, etc. At the present time, whether or not a given composition will exhibit most or any of these characteristics appears to be unpredictable. In numerous instances While one composition containing a certain ratio ofelements such as phosphorus, nitrogen, and halogen is efiective, a related composition containing the same ratio of the same elements may be entirely inefiective.

An object of the present invention is to provide novel liquid or solid thermosetting polymers which are characterized by a high resistance to burning and an ability to impart a resistance to burning to materials with which they are in contact and which are useful for the numerous uses made of thermosetting polymers. A further object is to provide aqueous textile treating liquids, consisting essentially of emulsions of such polymers in water, which are textile flammability reducing agents that are efiective in relatively small amounts, do not adversely alter the hand or feel of textiles impregnated with them and which are highly resistant to removal by laundering and dry cleaning.

In general, in accordance with this invention, phosphonitrilic ester adducts' are produced by' reacting at least one terminally unsaturated, polymerizable, alkenyl phosphonitrilic ester with at least one polyhalohydrocarbon containing at least two halogen atoms of the group bromine and chlorine attached to the same carbon atom, in the presence of a free radical reaction initiator, to produce a halomethylated alkenyl phosphonitrilic polyester adducf containing phosphorus, nitrogen, and halogen.

A preferred class of the polyester addncts provided by Patented Mar. 4, 1958 ice F iii T at in which n is an integer and A is a radical of the group R1 -RJJ-C(Ri)2 X CXY: and

R1 R1 R?m m. X(R1)20 C(RihCXY in which R is an alkylene radical, R is a hydrogen atom or an alkyl radical, X is a bromine or chlorine atom afid Y is a bromine, chlorine, or hydrogen atom. In the last formula, above, one of radicals, R, is attached to an oxygen in the group,

while the other R may be attached to a hydrogen, another X(R )zC C(ROzCXY: unit (to produce a structure similar to that shown in Patent No. 2,778,747, column 1, line 40), or to one of the recurring structural units of the formula L (Li.

In the last instance, the bonding would be through the oxygen. Where the structureis of the type shown in Patent No. 2,778,747, the chain would terminate with a hydrogen attached to the R. In the case of the polyester adducts of allyl phosphonitrilic esters, A represents radicals of the group -CHzOH-CH2 X exit:

and

This class of polyester adducts is produced when the polyhalohydrocarbon is a polyhalomethane of the formula CX Y in which X represents bromine or chlorine atoms and Y represents bromine, chlorine, or hydrogen atoms. Examples of such polyhalomethanes include compounds of the formula. CBr CBr Cl, CBl'gClg, CBrCl CBr H, CBr l-l C01 CCl H, and CClgHg;

In general, the terminally unsaturated, polymerizable, alkenyl phosphonitrilic esters which can be used comprise any such ester which is capable of undergoing a free radical induced polymerization. Such esters canbe produced by condensing a terminally unsaturated alkenyl' alcohol or its alcoholate with a phosphonitrilic halide with the elimination of hydrogen halide or a salt of a hydrogen halide, until the halide atoms of the phosphonitrilic halides have been replaced by alkenoxy radicals. i. e., a condensation in which [PNUElaUz] [PNTORM] where Hal represents a halogen atom, 11 an integer, and R a terminally unsaturated alkenyl radical. Such esters can be produced by employing a terminally unsaturated alkenyl alcohol or its alcoholate in processes such as those described in U. S. Patents Nos. 2,192,921, 2,214,769, or 2,586,3 12. Whether a given alkenyl phosphonitrilic ester is capable of undergoing free radical induced polymerization can readily be determined by heating the ester in the presence of free radicals, e. g., those formed by a peroxide at its decomposition temperature, and observing the viscosity of the so-treated ester. If the viscosity has increased, the ester is suitable for employment in the present process. In general, such alkenyl esters of the lower, i. e. the organic solvent soluble, phosphonitrilic chlorides such as the trimers, tetramers and mixtures in which they predominate are preferred.

In general, the use of terminally unsaturated alkenyl phosphonitrilic esters in which the alkenyl radicals contain from 2 to 6 carbon atoms is preferred; and the use of such allylic esters (those in which the alkenyl radical has the formula CH CR=CH in which R is an alkyl radical) is particularly preferred. Illustrative examples of suitable alkenyl phosphonitrilic esters include the vinyl, allyl, propargyl, metallyl, 4-pentenyl, 2,4-pententadienyl and the like esters.

The use of terminally unsaturated alkenyl phosphonitrilic esters which are viscous liquids is preferred. Such esters can be produced by esterifying polyphosphonitrilic halides or by thermally polymerizing the alkenyl phosphonitrilic esters. The use of viscous liquid esters having a molecular weight in the order of 700 is particularly preferred.

In general, the hydrocarbons containing at least two halogen atoms of the group bromine and chlorine attached to the same carbon atom which can be used comprise. any such compound capable of undergoing a free radical initiated reaction in which the reactive functional groups combine in accordance with CX C: C CXCCX where X is a bromine or chlorine atom. A preferred class of such polyhalohydrocarbons consists of compounds of the group and in which X represents bromine and Y represents a bromine, chlorine, or hydrogen atom. The polyhalomethanes of the formula CX Y are particularly preferred. Illustrative examples of suitable polyhalohydrocarbons include bromoform, carbontetrobromide, tribromotrichloroethane, the dibromodichloroethanes and the like.

Free radical reaction initiators which can be used include substantially any compounds which are susceptible to being decomposed to yield free radicals under the in fiuence of heat, light, or fast elemental particles formed in the course of the reaction. Illustrative examples of suitable free radical reaction initiators include peroxides such as dibenzoyl peroxide, di-tertiary-butyl peroxide, hydrogen peroxide, alkali metal persulfates, benzoyl hydroperoxide, cumene hydroperoxide, and the like; azo compounds such as 2,2'-bisazoisobutyronitrile; junction with actinic light and the like reaction initiators. The peroxides and, where the reaction is conducted in an aqueous emulsion reaction medium, the water soluble peroxides, are particularly preferred reaction initiators.

The liquid or solid halomethylated alkenyl phosphonitrilic polyester-adducts produced in accordance with this,

listen-es in coninvention are thermosetting polymers which are highly resistant to burning and which are generally useful wherever any thermosetting polymers are used. They are useful in the production of molded synthetic plastic articles such as buttons, containers, electrical insulators, and the like; coatings such as paints, varnishes, and the like. They are particularly useful as textile treating agents for reducing the flammability of the textiles and, in this connection, they can be applied to the textiles from organic solutions or aqueous emulsions of dispersions and can suitably be applied to textile materials in the form of fibers, sliver, yarns, threads or fabrics. V

Particularly valuable textile treating processes in which they are used in conjunction with other polymeric materials to impart a particularly strong resistance to burning to organic textiles are described in greater detail in copending application Serial No. 467,899, filed of even date.

The reaction of the alkenyl phosphonitrilic esters with the polyhalohydrocarbon can be conducted under widely varying conditions and by widely differing reaction procedures. While it is not required, the use of a liquid diluent is generally preferred. Substantially any liquid, which is unreactive toward the ester and the halohydrocarbon and is a suitable solvent or dispersing medium for them and the free radical initiator, can be used. Illustrative examples of liquids which can be used include water; hydrocarbons such as the pentanes, the hexanes, benzene, toluene, and the like; ethers such as diethyl or diphenyl ether, and dioxane; ketones such as acetone, and methyl ethyl ketone; and the like relatively unreactive liquids.

The reaction between the ester and the halohydrocarbon can be conducted under pressures above or below atmospheric and at any temperature between the temperature at which the reactants or the reaction medium is solid to the decomposition temperature of the ester or the hydrocarbon. In general, the use of atmospheric pressure and a peroxide reaction initiator which decomposes to yield free radicals at a reaction temperature of from about to C. is preferred.

The proportion of unsaturated groups contained in the polyester adducts provided by this invention can be varied widely by varying the reaction time and/ or the proportion of polyhalohydrocarbon used. In general, the proportion of unsaturated groups in the polyester adduct decreases with increases inreaction time. Particularly where the polyester adducts are to be used as textile flammability reducing agents, it is generally preferable to select the proportionate amount of polyhalohydrocarbon to provide a ratio of halogen to phosphorus of from about 2 to 6 parts halogen per part of phosphorus and the reaction conditions to react substantially all of the polyhalohydrocarbon. The use of from about 1/3 to 4/3 moles of polyhalohydrocarbon per mole of alkenyl phosphonitrilic ester is particularly preferred.

In a particularly preferred embodiment, the present invention provides aqueous emulsion textile flammability reducing agents which are aqueous emulsions consisting essentially of the polyester adducts, water, and a small amount of an emulsifying agent. While the polyesteradducts can be separately prepared, by a reaction in the absence of a diluent or in an organic solvent, and then emulsified with water, the aqueous emulsions containing them are preferably producedby forming an emulsion containing the alkenyl phosphonitrilic ester, the polyhalomethane, water, and the free radical reaction initiator and producing the polyester-adducts in situ.

A particularly suitable method of producing the aqueous emulsions containing the polyester adduct comprises forming an aqueous emulsion containing the alkenyl phosphonitrilic ester, the polyhalomethane, a water soluble peroxide and a small but effective amount of an emulsifying agent, and heating the emulsion to a temperature at which the peroxide forms free radicals, until the emulsion contains a phosphorus, nitrogen, and halogen containing polymer, In general, aqueous emulsion textile treatins ag nt ha ng a r l y hi h ga materi l tent are generally preferred. In the production of concentrated aqueous emplsions in accordance with the present process, it is preferable to conduct the reaction in an aqueous emulsion which contains enough reactants to provide the desired concentration of resinous material and which has a pH of from about 5 to 8. The pH of the aqueous emulsion can be adjusted by the incorporation of the necessary amount of a water soluble weak base. Suitable weak bases include inorganic bases such as the alkali metal bicarbonates, and organic bases such as pyridine, dimethylaniline, triethanolamine and the like. In general, the use of from about 5 to parts of an alkali metal bicarbonate per 100 parts of phosphonitrilic ester is preferred.

Substantially any of the conventional emulsifying agents can be used in the present process. As is known to those skilled in the art, emulsifying agents vary widely in cost as well as in the amount of agent required to emulsify a given mixture of immiscible liquids. Since, in order to obtain a rapid reaction, a reaction medium should be as uniform, as concentrated, and as non-viscous as is possible, the choice of a particular emulsifying agent will depend upon its capacity to produce uniform emulsions when used in quantities not unduly raising the viscosity of the emulsion balanced against the cost of the emulsifying agent and the cost of a slower or less eflicient reaction. Suitable emulsifying agents include the polyvinyl alcohols, the sulfated alcohols, dioctyl sodium sulfosuccinate, isopropyl naphthalene sodium sulfonates, ammonium oleate, a carboxymethylcellulose, the resin soaps, and the like emulsifying agents. The polyvinyl alcohols of medium viscosity are particularly suitable.

Substantially any water soluble peroxidic polymerization catalyst which forms free radicals at a relatively rapid controllable rate of temperature below about 200 C. can be used in the production of the aqueous suspensions provided by the present invention. Such catalysts include H 0 the water soluble persulfates, the water soluble organic hydroperoxides or their salts, the water soluble organic peracids, and the like peroxidic catalysts. The sodium, potassium and ammonium persulfates are particularly suitable.

The reaction time necessary to produce the aqueous emulsion flammability reducing agents provided by this invention, in each particular case, depends upon the alkenyl phosphonitrilic ester, the halomethane, and the catalyst used, as well as upon the concentration and proportions of the reactants in the aqueous emulsion constituting the reaction mixture. When the nonaqueous phase of the reaction mixture contains a dispersed polymer containing phosphorus and halogen, the reaction can be terminated. The suitability of the use of longer reaction times is dependent upon the economics of the cost introduced by the additional time and energy spent in using up more reactants.

The proportions of the peroxidic polymerization catalyst can be varied widely. The results of using large or small amounts, based on the weight of the polymerizable reactant, are analogous to those generally obtained in emulsion polymerization reactions. The employment of from about 0.01 to 0.03 mole of catalyst per mole of phosphonitrilic reactant is preferred.

The proportion of organic reactants and the proportion of emulsifying agent in the aqueous emulsion constituting the reaction mixture can also be varied widely. It is, of course, advantageous to use as little of the emulsifying agent and water as can be used in producing a relatively fluid emulsion in which the reactants are uniformly mixed. The use of about 1 part of a medium viscosity polyvinyl alcohol in about 100 parts of water emulsified with about 50 parts of organic reactants has been found to be particularly suitable.

In general, in reducing the flammability of organic textiles in accordance with this invention, it is preferable to impregnate the text es with a relatively volatile liquid containing further reactable polymeric ester adducts and to. The.

further react the ester adducts in situ in the textile. use of aqueous emulsions is preferred. The textiles impregnated with the relatively volatile liquid containing the polyester adducts are preferably dried by heating them to from about 80 to 110 C. for from about 4 to 10 minutes, with the lower temperature being used with the longer time, to dry the textile by evaporating volatile materials. The impregnated and dried textiles are preferably heated at from about 120 to 150 C. for from about 4 to 10 minutes using the lower temperature with the longer time to further react the polyester adducts and convert them to insolubilized resinous materials.

The impregnation of organic textiles with relatively volatile liquids containing the polyester adducts can be con ducted by means of the usual textile impregnation procedures and apparatus. Where a high resinous material add-on is desired it is preferable to employ a plurality of impregnation and drying steps.

lubricating, and the like textile treating agents before or after the polyester adducts are applied to the textile or insolubilized in situ in the textile.

The folowing examples are illustrative of the invention. The alkenyl phosphonitrilic esters used in the examples were prepared by reacting 116 parts by weight of substantially trimeric phosphonitrilic chlorides with 162 parts ofthe sodium alcoholate of allyl alcohol dissolved in benzene. The allyl phosphonitrilic esters so produced were viscous liquids having molecular weights of from about 720 to 770.

In the examples, the flame resistance of various resin impregnated cloths were compared by the strip flame test method. In this method a strip of the cloth, which is about half an inch wide and about 3 inches long, is supported at one end so that the strip extends toward somedegree between 0 and 180 relative to a vertical azimuth. The unsupported ends of the cloth strips are ignited by contacting them with a flame until the cloth begins to burn. As soon as the cloth is ignited the flame used to ignite it is removed. The flammability of the cloths is compared on the basis that when so supported and ignited the cloths have a much greater tendency to burn when they are supported so that they extend straight down and thus are ignited at the bottom. Untreated cellulosic cloth will fail at 0 degrees (i. e. will burn when supported to extend straight up and ignited at the top). A very flame resistant cloth will pass at 180 (i. e. will not burn when supported to extend straight down and ignited at the bottom). A

relatively flame resistant cloth will not fail except at some:

degree between about 90 and 180 (i. e. when supported to extend at least somewhat downwardly so that the flame is propagated at least somewhat upwardly).

Example 1 An allyl phosphonitrilic-bromoform polyester adduct was prepared from 0.6 mole of bromoform per mole of ester by forming an emulsion containing about 16 parts of the ester, 15 parts of bromoform, 1.5 parts of sodium bicarbonate, and 0.6 part of polyvinyl alcohol as an emulsifying agent in parts of water. The emulsion was heated to a temperature of about C. and about 0.6 part of potassium persulfate was added. The emulsion was maintained at about 80 to 86 C. for about an hour. A stable emulsion containing a phosphorus, nitrogen, and halogen containing polymer was produced.

A piece of 8 oz. cotton twill was impregnated with the above emulsion to a wet pickup of 65%. it was dried at C. for 10 minutes then cured at C. for 6 minutes. It was finally washed 15 minutes in hot tap water and then dried. The change in weight indicated a resin pickup of 12.9%. It passed the (vertical).

strip flame test, had a char length of 4.82 inches and.

lost approximately 20% in tear strength. An analysis of the fabric gave nitrogen=0.65%, phosphorus=1.37% and bromine 4.19%.

Example 2 An allyl phosphonitrilic-bromoform polyester adduct was prepared from 0.4 mole of bromoform per mole of ester by forming an emulsion containing about 29 parts of the ester, 18 parts of bromoform, 4.6 parts of sodium bicarbonate, and 0.9 part of polyvinyl alcohol as an emulsifying agent in 107 parts of water. The emulsion was heated to a temperature of about 80 C. and about 0.9 parts of potassium persulfate was added. The emulsion was maintained at about 80 to 86 C. for about an hour. A stable emulsion containing a dispersed phosphorus, nitrogen, and halogen containing polymer was produced.

A piece of 8 oz. twill was padded with the emulsion, dried, cured and washed as in Example 1. Its final gain in weight was 10.9%. It passed the 180 (vertical) strip flame test. Its durability to 3 and 6 QM laundry cycles was tested. These results are found in the table.

1 Federal Specification No. CCC-T-191b. 2 AATCC Standard Test Method 34-52.

Example 3 A bromine-containing allyl phosphonitrilic ester was prepared using 0.6 moles of bromoforrn per mole of phosphonitrilic ester by the process described in Example 1.

A piece of 8 oz. twill was impregnated with the emulsion, dried, cured and washed as in Example 1. Its final gain in weight was 14.7%. It passed the 180 (vertical) strip flame test. Its durability to 3 hours alkaline soap boil (0.5% soap and 0.2 carbonate) and to QM laundry cycles was tested. These results are found in One half a sample A was given 5 QM laundry cycles (Federal Specification No. CCC-T-191b). One half of sample B was boiled minutes in 1% NaOH'solution. One half of sample C was boiled '30 minutes in alkaline soap solution (0.5% soap and 0.2% Na CO The tests on these samples are reported in the following table.

i Elmen- Change Trape- Change Sample Desigdort in zoid in Char nation Tear Strength Tear Strength Length 1 Strength Strength 1 Lbs. Percent Lbs. Percent In. 1 3. 1 8. 4 20 5. 20 3. 1 8. 7 18 5. 78 3. 1 35 8. 4 20 4. 95 3. l 35 8. 1 24 5. 05 3. 1 --35 8. 2 ---22 4. 10 3. 5 27 9. 4 1l 6. 85 4. 8 10. 6 -l 1 Federal Specification No. CCCT191b. I AATCC Standard Test Method 34-52.

I claim: 1. A resinous polymer having recurring structural units of the formula in which n is an integer and A is a radical of the group consisting of R1 RA-C(31):

GXY,

and

R1 R1 -RC( 3R- X Rl 2 $(R1)2CXY1 in which R is an alkylene radical, R is a radical from the group consisting of H and alkyl, X is a halogen radical from the group consisting of bromine and chlothe table. rme, and Y is a radical selected from the group con- Sample Elmen- Change Trape- Change Desrgna Alter Treatment dori in acid in Char tron Tear Strength Tear Strength Length 1 Strength Strength Lbs. Percent Lbs. Percen In.

3.3 10.2 10. 3. 4.6 +7 13.2 +15.8 7 95-BEL 3. 6 l6 12. 4 +8. 8 5. Control. 4. 3 l1. 4

1 Federal Specification No. CCC-T-lQlb. AATCC Standard Test Method 34-52.

Example 4 Sample Designation Wet Pickup Cured Pickup Final Pickup Percent 66 69 71 Percent 15. 2 18. 6 17. 2

Percent Oad HHls wsisting of H, bromine and chlorine, one of the Rs in the radical,

RCCR Xutmb C(RmCXYz being attached to an oxygen in the group,

and the other R being attached to a radical selected from the group consisting of hydrogen, one of the units and another radical,

in which n is an integer and A is a radical from the group consisting of CH OH-CH X CXY: and

in which X is a halogen radical from the group consisting of bromine and chlorine and Y is a radical from the group consisting of H, bromine, and chlorine, one of the Rs in the radical,

R1 R1 RC(IJR (R1)s( 3 (iKRihCXY; being attached to an oxygen in the group,

and the other R being attached to a radical selected from the group consisting of hydrogen, one of the units and another radical,

R1 R1 R(il(3R- X(R1)2( 3 J(R1)zCXYg 3. A textile flammability reducing composition comprising an aqueous emulsion of a polymer having recurring structural units of the formula :11 L in.

in which n is an integer and A is a radical from the group consisting of -CH;CHCHg KY: and

in which X is a halogen radical from the group consisting of bromine and chlorine and Y is a radical from the group consisting of H-, bromine, and chlorine, one of the Rs in the radical,

10 and the other R being attached to a radical selected from the group consisting of hydrogen, one of the units,

L (Ll.

and another radical,

4. A process of producing alkenyl phosphonitrilic ester adducts comprising reacting at least one alkenyl phosphonitrilic ester in which the alkenyl radical contains from 2-6 carbon atoms, with at least one polyhalomethane containing a plurality of halogen atoms selected from the group consisting of bromine and chlorine in the presence of a free radical reaction initiator to produce a halomethylated allsenyl phosphonitrilic polyester-adduct containing phosphorus, nitrogen, and halogen.

5. A process of producing an allyl phosphonitriiic ester adduct comprising reacting an allyl phosphonitrilic ester with at least one polyhalomethane containing a plurality of halogen atoms selected from the group consisting of bromine and chlorine in the presence of a free radical re action initiator to produce a halomethylated allyl phosphonitrilic polyester adduct containing phosphorus, nitrogen, and halogen.

6. A process of producing a textile flammability reducing composition comprising forming an aqueous emulsion containing at least one alkenyl phosphonitrilic ester in which the alkenyl radical contains from 2-6 carbon atoms, at least one substituted methane having halogen substituents selected from the group consisting of bromine and chlorine, said substituted methane having at least two of said halogen atoms, a free radical reaction initiator, and a small amount of an emulsifying agent, and maintaining the emulsion at a temperature at which the free radical initiator yields free radicals until the emulsion contains a phosphorus, nitrogen, and halogen containing polymer.

7. T he process for producing a resinous polymer which comprises mixing a diallyl phosphonitrilic ester with bromoform in the presence of potassium persulfate and heating the mixture until a polyester containing phosphorus, nitrogen, and bromine is produced.

8. A process for producing a textile flammmability reducing composition which comprises forming an aqueous emulsion of a diallyl phosphonitrilic ester and bromoform, adding to said emulsion potassium persulfate, and heating said emulsion to produce a stable emulsion of a polyester containing phosphorus, nitrogen, and bromine.

9. The process for reducing the flammability of a textile which comprises impregnating said textile with the stable emulsion obtained by the process of claim 8, drying the impregnated textile, and then insolubilizing the impregnant in situ at an elevated temperature.

References Cited in the file of this patent UNITED STATES PATENTS Lipkin Sept. 17, 1940 Frick Aug. 17, 1954 OTHER REFERENCES 

1. A RESINOUS POLYMER HAVING RECURRING STRUCTURAL UNITS OF THE FORMULA 